Diquat

Diquat dibromide

Names
IUPAC name 6,7-Dihydrodipyrido[1,2-a:2',1'-c]pyrazinediium dibromide
Other names 1,1'-Ethylene-2,2'-bipyridyldiylium dibromide
Identifiers
CAS Registry Number	85-00-7 Y
ChEMBL	ChEMBL1599022 N
ChemSpider	6536 Y
InChI InChI=1S/C12H12N2.2BrH/c1-3-7-13-9-10-14-8-4-2-6-12(14)11(13)5-1;;/h1-8H,9-10H2;2*1H/q+2;;/p-2 Y Key: ODPOAESBSUKMHD-UHFFFAOYSA-L Y InChI=1/C12H12N2.2BrH/c1-3-7-13-9-10-14-8-4-2-6-12(14)11(13)5-1;;/h1-8H,9-10H2;2*1H/q+2;;/p-2 Key: ODPOAESBSUKMHD-NUQVWONBAO
Jmol-3D images	Image
KEGG	C18577 Y
PubChem	6794
SMILES [Br-].[Br-].c2cccc3c1[n+](cccc1)CC[n+]23
UNII	A9A615U4MP Y
Properties
Molecular formula	C12H12Br2N2
Molar mass	344.05 g·mol−1
Appearance	Yellow crystals[1]
Density	1.22 - 1.27 g/cm3
Melting point	335 °C (635 °F; 608 K)
Boiling point	Decomposes[1]
Solubility in water	70% (20°C)[1]
Vapor pressure	<0.00001 mmHg (20°C)[1]
Hazards
US health exposure limits (NIOSH):
PEL (Permissible)	none[1]
REL (Recommended)	TWA 0.5 mg/m3[1]
IDLH (Immediate danger)	N.D.[1]
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
N verify (what is: Y/N?)
Infobox references

Diquat is a contact herbicide that produces desiccation and defoliation most often available as the dibromide, diquat dibromide.^[2] Brand names for this formulation include Aquacide, Dextrone, Preeglone, Deiquat, Detrone, Reglone, Reglon, Reglox, Tribune, Ortho-Diquat, Weedtrine-D,^[3] Weedol 2 and, in combination with glyphosate, Resolva.^[4]

Diquat is a non-selective herbicide that acts quickly to damage only those parts of the plant to which it is applied.^[5] It has been used in pre-harvest crop desiccation.^[6] It bonds strongly to mineral and organic particles in soil and water where it remains without significant degradation for years. However, bound to clays diquat is biologically inactive at concentrations typically observed in agricultural soils.^[5]

Diquat dibromide is moderately toxic. It may be fatal to humans if swallowed, inhaled, or absorbed through the skin in large quantities.^[5]

Production

Pyridine is oxidatively coupled to 2,2'-bipyridine over a heated Raney nickel catalyst. The ethylene bridge is formed by the reaction with 1,2-dibromoethane:^[7]

See also

• Paraquat

References

1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 "NIOSH Pocket Guide to Chemical Hazards #0243". National Institute for Occupational Safety and Health (NIOSH). 
2. ↑ Merck Index, 11th Edition, 3359.
3. ↑ PubChem listing for diquat dibromide
4. ↑ Weedkillers for Home Gardeners. RHS Advisory Service, Royal Horticultural Society, February 2013. Accessed May 2013.
5. ↑ 5.0 5.1 5.2 EXTOXNET, Pesticide Information Project
6. ↑ "The agronomic benefits of glyphosate in Europe" (PDF). Monsanto Europe SA. February 2010. Retrieved June 2, 2013. 
7. ↑ "Paraquat and Diquat". IPCS INCHEM.